Hydraulic crane device



Oct. 18, 1960 K. o. FRISK 2,956,690

HYDRAULIC CRANE DEVICE Filed April 2:, 195a United States Patent HYDRAULIC (IRANE DEVICE Rant 0. Frlsk, Bracke, Sweden Filed Apr. 23, 1958, Ser. No. 730,330

Claims priority, application Sweden Apr. 24, 1957 2 Claims. (Cl. 212-35) This invention relates to a hydraulic crane device adapted to be attached to trucks, tractors and the like.

The main object of the invention is to provide an im.-' proved crane-device in which the crane beam is permitted to unimpededly swing about the vertical axis of the crane post and to perform a lifting movement independent of the operation of a hoisting machinery in the crane beam and in which the various movements of the crane beam and hoisting means may be operated by means of a single operating member.

The crane device has a crane beam including a hydraulic hoisting machinery and being movable up and down by means of a hydraulic ram engaging with the beam at distance from the rear end of the latter. The rearwardly projecting part of the beam is by a linkage connected with a cantilever structure rotatable with the beam about the vertical axis of the crane post.

Another object of the invention is to provide the cylinder for said ram as a stationary post for the crane, thereby simplifying the mounting of said post.

A further object of the invention is to provide an elongated tube-shaped ram freely rotatable in said cylinder and containing a telescope pressure fluid conducting tubing concentric with the ram and having its parts freely rotatable relative to each other for supplying pressure fluid to hydraulic means in the crane beam, such as hoisting machinery.

Still another object is to provide a link connection between the rear end of the crane beam and the rotatable cantilever structure, said link being variable to its length and lockable in its adjusted position, thereby permitting the lifting movement to be varied within wide boundaries.

Said telescope tubing may comprise an arbitrary number of concentric tubes forming annular channels for conducting pressure fluid to various means in the jib, for lengthening or shortening said link, a telescope jib or the like.

Other objects and advantages of the invention will appear from the following description of a preferred embodiment of a crane devicewith reference to the accompanying drawings.

Fig. l of the drawings is a part sectional elevation of a hydraulic crane device.

Fig. 2 is an elevation of a part of the crane device in diflerent positions of adjustment.

Fig. 3 is a fragmentary large scale perspective view, partly in section, showing a detail of the crane of Fig. l.

The crane device comprises a cylinder forming a post 1 and supporting slidable therein a tube shaped ram 2, which is freely rotatable in the cylinder and sealed at the upper end 3 of the cylinder. The ram 2 may be lifted and lowered by pressure fluid supplied from a control valve device 31 through an opening 4 and through openings 25 and 27.

The ram 2 supports at its upper end a head 5 provided with a pivot connection for the crane beam or jib 7. The pivot connection 6 is located at a distance from the rear end of the jib 7. The rear end of the jib 7 is at 9 by means of a variable link 8 pivotally connected with an bearing structure may suitably comprise a pair of oppositely arranged conical roller bearings 13, 14.

Said sleeve 12 includes further an upper bushing 15 in which the ram 2 is slidably supported and guided. An

annular bushing 16 in the cylinder 1 forms lower ram guiding means.

When the ram 2 is through the operation of the valve device 31 lifted or lowered the jib 7 will swing upwardly or downwardly about the fixed pivot points 9, 10 of the link 8 and the pivot connection 6 with the ram head 5. .By varying the length of the link 8 the angular position of the jib 7 at a given position of the ram 2 will be ditierent so that the reach of the jib will be increased at high lift. This is of great advantage when large bulky objects, timber or the like are to be lifted, which requires at the same time a high lift and a large reach.

The embodiment shown is provided with a simple link comprising two parts 8a and 8b (Fig. 2), having corresponding holes 17 which may be brought in register with each other in different positions of the parts as shown in Fig. 2 and the parts are locked in their adjusted positions by bolts 17'.

A hoisting machinery 18 is provided at the rear end of the jib adjacent to its pivot connection with the ram head 5.

The hoisting machinery comprises a hydraulic motor 19 driving a cable drum 20. To supply the motor 19 with pressure fluid without impeding upon the rotational movement of the jib two concentric telescope tubes 21, 23 and 22, 24 respectively are arranged within the cylinder 1 and ram 2 concentric therewith. Sealing elements 25 provide for a tight slidable and rotatable connection of the tubes. At the bottom of the cylinder and head 5 of the ram 2, supply and discharge conduits 25', 26 and 27, 28 respectively are connected with the central tube 23, 24 and the annular space between the tubes 23, 24 and 21, 22. The conduits 25', '27 are connected with suitable valve members in the valve device 31 and the conduits 26, 28 in the ram head 5 are by means of flexible tubes 29, 30 connected with the hydraulic motor 19. The flexible tubes 29, 30 are adjusted to the maximum lifting movement of the jib. It is to be noted that the adjustment of the length of the link 8 has no influence on the flexible tube connection.

Power is transmitted from the rotary hydraulic motor 19 through gears 60, 61, 62 (Fig. 3) to the cable drum 20. The gears 60, 62 are secured to the shaft of the motor 19 and to the cable drum 20, respectively. The intermediate gear 61 is idle serving the purpose of transmitting the rotary movement from the gear 60 to the gear 62. The cable is designated with 63. The rotary motor 19 is a necessary part of the hoisting machinerythe motor 19 driving the cable drum 20. Any type of conventional electric motor may be used in order to transmit power.

Any number of telescope tubes may be arranged in the cylinder 1 and ram 2 for supplying pressure fluid to other Patented Oct. 18, 1960 jib or by means of the hoisting machinery or by both, which in combination with the variable link facilitates the loading of objects differing in size,

The valve device 31 for controlling the various hydraulic means of the crane device is shown only schematically in Fig. 1.

I claim:

1. In a hydraulic crane having a jib turnable about a vertical axis and having hydraulic hoisting means, in combination, a stationary hydraulic cylinder, a ram rotatably and vertically slidably disposed in said cylinder and open at the bottom, means operable for delivering pressure fluid to the interior of said cylinder and ram for raising and lowering respectively said ram relative to said cylinder, a support connected to the exterior of said cylinder and operable for supporting one portion of said jib, means establishing a pivot connection between the top of said ram and another portion of said jib, whereby upon vertical movement of said ram said jib will be tilted, and means operable for delivering from the interior of said ram into the interior of said jib the pressurized fluid to energize said hoisting means comprising at least two telescopic tubes concentric with said ram, one tube being connected to said cylinder and the other tube to said ram, said pressure fluid delivering means delivering pressure fluid to the interior of the tube in said cylinder, and flexible conduit means adapted to be connected to said hoisting means in the jib and being connected to said tube in said ram.

2. In a hydraulic crane as claimed in claim 1, said support being rotatable on said cylinder, a link interconnecting one portion of said-jib, with said support, said link being of variable length and operable to be lockable in adjusted positions of length, whereby said one portion of said jib may be positioned at varying distances from said support.

References Cited in the file of this patent UNITED STATES PATENTS 2,462,926 Wilson Mar. 1, 1949 2,528,588 Forslund Nov. 7, 1950 2,672,990 Sundin Mar. 23, 1954 2,792,127 Nielsen May 14, 1957 2,828,867 Frisk Apr. 1, 1958 

